The present invention is generally related to using human position and movement, as well as other visual cues, as input to an interactive system that reorients one or more directed light or sound sources and modifies their content in real time based on the input.
Detecting the position and movement of a human body is referred to as “motion capture.” With motion capture techniques, mathematical descriptions of a human performer's movements are input to a computer or other processing system. Natural body movements can be used as inputs to the computer to study athletic movement, capture data for later playback or simulation, enhance analysis for medical purposes, etc.
Although motion capture provides benefits and advantages, motion capture techniques tend to be complex. Some techniques require the human actor to wear special suits with high-visibility points at several locations. Other approaches use radio-frequency or other types of emitters, multiple sensors and detectors, blue-screens, extensive post-processing, etc. Techniques that rely on simple visible-light image capture are usually not accurate enough to provide well-defined and precise motion capture.
Some motion capture applications allow an actor, or user, to interact with images that are created and displayed by a computer system. For example, an actor may stand in front of a large video screen projection of several objects. The actor can move, or otherwise generate, modify, and manipulate, the objects by using body movements. Different effects based on an actor's movements can be computed by the processing system and displayed on the display screen. For example, the computer system can track a path of the actor in front of the display screen and render an approximation, or artistic interpretation, of the path onto the display screen. The images with which the actor interacts can be e.g., on the floor, wall or other surface, suspended three-dimensionally in space, displayed on one or more monitors, projection screens or other devices. Any type of display device or technology can be used to present images with which a user can control or interact.
In some applications, such as point-of-sale, retail advertising, promotions, arcade entertainment sites, etc., it is desirable to capture the motion of an untrained user (e.g., a person passing by) in a very unobtrusive way. Ideally, the user will not need special preparation or training and the system will not use unduly expensive equipment. Also, the method and system used to motion capture the actor should, preferably, be invisible or undetectable to the user. Many real-world applications must work in environments where there are complex and changing background and foreground objects, changing lighting conditions and other factors that can make motion capture difficult.
Light beams created by simple flashlights, slide projectors, and video projectors, which are designed to project light or an image onto a specific location, can have their light reoriented in real time using mobile mirrors placed in front of the beam. These mirrors are often controlled by one or more stepper motors, allowing precise, computer-controlled movements. Larger motorized mounts can be controlled in a similar manner to redirect the beam by moving the entire light-producing device.
Recent work in the audio domain has produced speakers that can direct a sound beam in the same way that a spotlight directs a light beam. These speakers work by emitting directed ultrasound pulses that disturb the air in a nonlinear way so as to create audible sound in a particular direction.
In the theater and stage environments, there has been a lot of work on finding automated ways for a spotlight to track a moving person on the stage. Current solutions include having an RF (radio frequency) transmitter on the person and then using several detectors to triangulate the person's position. However, these solutions generally require the person being tracked to wear some type of transmitting device.
Hence, it would be desirable to provide an improved interactive directed light/sound system that allows effects to be generated more accurately and in a less intrusive manner.